Circle saw rpm...

[mrcaptainbob]

A friend asked me to check with the FF for this. What is a recommended rpm for a 48"/50" circle saw? I know nothing else about it....

[weisyboy]

tip speed of 9000 - 11000 foot per minute

[tyb525]

500-600 rpm is a common speed they are hammered for. However, it could be different. But it's often around 540, tractor PTO wpeed.

http://www.thinkerf.com/circular_saw_feeds.htm

A neat link for the subject.

[weisyboy]

no a 50" saw should be around 800rpm.

[schmism]

now see it was my understanding that it was not just a straight forward number.

that a number of variables had to be considered durring saw setup including

size of blade
number of teeth in blade
HP input
anticipated (normal) feed rate
and of course hammered speed. 

it was my understanding that all the above work together to affect the efficiency of the mill.

in addition to the tip speed number i thought i had heard of a combined number of something like teeth inch speed per foot or something.  basicly relating the number of teeth to the feed rate to the rpm of the blade. 

[weisyboy]

it dose vary with each blade, witch is why i said 9000 - 11000 fpm, you have to adjust the speed untill you get the saw to stand up.

i have had 1 or 2 blades we had to drop to 8000 but usualy within that range.

[bandmiller2]

This question comes up all the time.Break circular mills into two groups older handsets and newer modern high speed mills.The newer mills use the speeds Weasy is talking about.The old handsets and headsaws are more comfortable and were designed to be in the 400 to 600 rpm range.Yes older saws can be hammered to high speed but are much harder to keep right.Each tooth should take a 1/10" bite if you have 50 teeth thats 5" per revolution a saw turning 750 rpm that carriage is flying.Alot of us older sawyers and mills are not up to that speed.On a heavy duty handset mill the carriage weighs about a ton and many logs weigh the same thats the weight of a full size car being started and stopped, thats why high speed mills are built so heavy.

[weisyboy]

we have always run saws that speed in australia.

maby we need the extra speed for our hardwood. feed speed is a different matter and is gaged by hp, the saws should be setup for a hp to take a bit that the engine can handle, a saw with 100hp can take mutch bigger bites than a saw with 50hp.

speed should be stamped on the saw close to the collar

[Ron Wenrich]

It seems we've been on this subject before.  I'm with bandmiller on this one. 

Speed is dependent on the setup of the mill.  Those older mills had the carriage speed coming directly off of the arbor.  So, if you were running a slower speed, your carriage ran at a slower speed.  Speed up the saw and the carriage speed came up as well.

You're looking at advancing the carriage at so much per revolution.  A lot of that speed will be dependent on certain variables, such as species, log size, hp, tooth sharpness and others.  Most sawyers know that you have to adjust your feed rate as those variables change.  You can feed a pine log a whole lot faster than a dried out hickory.  FPM doesn't come into the equation.  If you try to match your optimum FPM, you'll find that the hickory log will give a lot of poorly cut lumber. 

I have run both newer and older mills.  My current speed is 690 RPM, and it isn't one I would recommend for someone starting out.  You have to be able to maintain a saw that runs at that speed.  Most of those older mills do run at about 540 RPM.  Its a good speed to saw logs and to learn how to run mills without getting into too much trouble.  I've seen them run all the way down to 350 RPM, but that is way too slow. 

The important thing is to be able to maintain the RPM that the saw is hammered for.  You can have it hammered to any speed you want.  But, as a sawyer, your job is to maintain that RPM through the entire cut.  If you don't, your saw will lay over and heat, or cut off line and heat, or it will hang up and heat.  Heat is the enemy of the circle saw and will make it do things you won't like.  That's part of the art of sawing, and not so much the science. 

So, find a speed that you're comfortable with and have the saw hammered for it. 

[Autocar]

I always had mine hammered for 450 RPM because my governor wasn't real quick to pick the load up, the saw ran 550 but always pulled down so at 450 it stood up and did the job.

[captain_crunch]

 Pics would help If you need to Email em to babjfoster@msn.com(mention sawmll is mail so wife don't delete it) and I can post them for you. I am newbe also but I speed my saw till wobble is gone then watch it as is is sawing if it wobbles a bit I give it more throttle to stand it up

[jimparamedic]

The # of teeth also is needed to figure hp feed rate Also spin an insert tooth saw 1000 rpm you are loading a gun  Oh and do not forget plate thickness I use an 8ga saw 350rpm and only half the teeth

[black]

What would happen if one turned a 46'' carbide tip blade at 2000 rpm (hydraulic carriage)?

[Jeff]

Us old sawyers would go hide in a bunker.

[weisyboy]

What would happen if one turned a 46'' carbide tip blade at 2000 rpm (hydraulic carriage)?

probably nothing but cant say iv ever tried it.

how bout you try it and ill stand behind this big tree.

[Jeff]

Like I said before. Apparently you know nothing about the design of our. Circular head rig saws. Your last comment is just plain dangerous as applied to us.

[Ron Wenrich]

Turn it up and tell me how you think you're going to control that saw.  Your rim speed is about 275 mph.  I certainly wouldn't want to hit a knot at that speed.  It makes no difference that you run a hydraulic carriage or that you're using carbide. 

[weisyboy]

Like I said before. Apparently you know nothing about the design of our. Circular head rig saws. Your last comment is just plain dangerous as applied to us.

if that was directed at me,

it was a joke.

spinning it at that speed wont affect the saw, but youd wanna make sure everything was heald together or the whole lot would fly to bits, and that not even thinking about puting a log threw it.

like i said you try it and ill stand behind a big tree.

[Jeff]

weisyboy , It was directed at you and the reason being is that you have been injecting inaccurate saw speed stats into threads about circle saws that are NOT designed to run at those speeds.  You need to read the thread first and figure out if it is a saw that is just like the ones you run in your part of the world or not before you comment, otherwise you are for lack of a better word, polluting some of the forum content with inaccurate information.  I spent my entire working life running a circle headrig so I'm pretty sure I know of what I speak in regards to the lion's share of circle mill topics here. Now if you are taking about swingmill technology, I don't know crap.

[weisyboy]

i dont know what the iferance in your blades and ours would be, they look the same and do the same job.

iv only run a lucas mill for about 4 years since the local gov [I have typed a profane word that is automatically changed by the forum censored words program I should know better] down our sawmill.

we ran both tungsten, inserted tooth and steel blades up to 60" on canadian saws and saws right down to 6" on multi rip saws, we always hammered our own blades and never had a probelm.

we sold all our gear and went out of sawmilling for 12 months untill i found out i could operate a Lucas mil without a permit.

i have now found a site i can setup a sawmill on again and wish we hadnt sold all our gear.

the closest sawmill to here now has there saws running at 12000fpm at the tip faster than we ever spun ours, with 100+ hp electric motors on them, and the caridge travel that fast you have to run to keep up.

im not here to cause trouble and i dont spout BS.

what is the diferance between your saws and ours?

[Jeff]

Since I know nothing about your saws, I can't tell you the difference, but I can point you to what most of us consider the best informational guide to the common circular sawmill. You should be able to use that to find what the differences are.  http://www.fpl.fs.fed.us/documnts/misc/circsaw.pdf

[weisyboy]

here you go.

SAW SPEED
In general, for good saw performance, a rim speed of 8,000 to 9,000 feet per
minute is recommended for sawing hardwoods; 10,000 to 11,000 f.p.m. for
softwoods; and 6,000 to 7,000 f.p.m. for frozen woods. The relationship of saw
diameter and saw speed necessary to attain a predetermined rim speed is given

we lways used our baldes at between 9 and 11 thousand fpm.

[Jeff]

You can not extrapolate those figures without consideration to horsepower and tooth configuration.  You can't just slap that on a given diameter saw without further data. That's the problem with your numbers. If you are running a saw like the last one I saw you post with maybe only 10 teeth, (unlike any headrig saws I have ever saw) maybe you can get away with running a high rpm with a tractor and its low horsepower.  Read the whole manual. Don't just cherry pick to try and justify your numbers. They only apply if everything else fits. When you are talking about the typical saws and power sources referred to here most of the time, they don't.

[weisyboy]

the saws we ran had between 30 and 60 teeth. the hp of a saw should be governed by the speed and timber being cut, not the speed.

these blades i just got are made to run at high speed 14 - 18 thousand feet per minute, on low hp machines.

anyway im not here to make enemies, so ill leave it at that.

[Ron Wenrich]

How's that supposed to work?  The lesser teeth and higher rpm factor.  I do know that the higher the rpm, the harder it is to maintain a saw.  I also know that if you don't have the hp to move the log through the saw, the saw dies, and you cut off line.  Running a saw fast and having it cut good lumber are two different animals.  Are they guided saws?

I can cut good lumber on good logs with less maintainence.  But, get into some hard, knotty logs, and things change very drastically, and in short order.  Just a little nick on a few teeth will pull the saw.  If you've ever sawn with a vertical edger, you will know exactly what I mean.  Vertical edgers will get you to sawing where your saw doesn't dish.

My understanding of Australian hardwoods is that they are much harder than those in the US.  So, that would tell me that you can't have the feed rates that we have.  It would be akin to those frozen hardwood logs that Lundstrum talks about.  The sawdust coming off of dense hardwoods like black locust and hickory is much finer than that of hardwoods like oak or ash.  There is a problem of sawdust filtering out of the gullets, down the side of the saw, and causing heat.  The saw then lays over, and the problems compound. 

I can see where you could raise your rpm and feed rates, but not lower your hp.  But, that would be more for cutting softwoods, like radiata pine.  Raising the rpm is to get more teeth through the log at a higher rpm.  Your bite would be the same, about 1/8" per tooth.  But, I just can't imagine how you compensate for knot dodge at that rate of speed or the density of the wood. 

From my observations of US hardwood mills is that I always figured that someone else has come up with some pretty reliable figures.  It comes from past experience and common sense approach to milling.  I have yet to see hardwood mills run at speeds you're talking about, irrespective of saw diameter.  I don't try to reinvent the wheel.  Top end mills over on this side run about 700 rpm.  The norm is 550 rpm, especially on older mills.  I always figured that a bunch of other guys have tried what I've been thinking about and found out that the norm works pretty well.  And I've done a lot of tinkering.

It sure would be nice if we could see each other's mills run.  I'm not talking about a few clips on youtube.  I mean where you can get to see the whole operation.  It sure would be a learning experience on both ends.   ;)